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Biotechnology Reports (Amsterdam,... Dec 2021In this study, three wastes based on potato peels and pulps, tomato seeds and wheat bran were used as basis for the preparation of a cheap medium to produce the...
In this study, three wastes based on potato peels and pulps, tomato seeds and wheat bran were used as basis for the preparation of a cheap medium to produce the bacterium PGP01. In flasks experiments, PGP01 growth at 25 °C in a medium based on frozen potato peels and pulp (FPP) with tryptone as a nitrogen source resulted in the maximum production compared to the commercial TSB medium. In the scale-up to 2 L bioreactors, FPP supplemented with tryptone, molasses, NaCl and KHPO allowed to reach similar biomass production than in the TSB medium. A maximum growth of 4.4 × 10 CFU mL after setting the agitation and the air flux conditions at 400 rpm and 0.75 vvm. Finally, PGP01 growing in this optimized medium conserved its biological activity showing the expected effect in root development previously reported for this microorganism.
PubMed: 34603978
DOI: 10.1016/j.btre.2021.e00675 -
Nanomaterials (Basel, Switzerland) Sep 2021We studied the effects of new chemically synthesized selenium (Se) nanocomposites (NCs) based on natural polysaccharide matrices arabinogalactan (AG), starch (ST), and...
We studied the effects of new chemically synthesized selenium (Se) nanocomposites (NCs) based on natural polysaccharide matrices arabinogalactan (AG), starch (ST), and kappa-carrageenan (CAR) on the viability of phytopathogen , rhizospheric bacteria, and potato productivity in the field experiment. Using transmission electron microscopy (TEM), it was shown that the nanocomposites contained nanoparticles varying from 20 to 180 nm in size depending on the type of NC. All three investigated NCs had a fungicidal effect even at the lowest tested concentrations of 50 µg/mL for Se/AG NC (3 µg/mL Se), 35 µg/mL for Se/ST NC (0.5 µg/mL Se), and 39 µg/mL for Se/CAR NC (1.4 µg/mL Se), including concentration of 0.000625% Se (6.25 µg/mL) in the final suspension, which was used to study Se NC effects on bacterial growth of the three common rhizospheric bacteria , and isolated from the rhizosphere of plants growing in the Irkutsk Region, Russia. The AG-based Se NC (Se/AG NC) and CAR-based Se NC (Se/CAR NC) exhibited the greatest inhibition of fungal growth up to 60% (at 300 µg/mL) and 49% (at 234 µg/mL), respectively. The safe use of Se NCs against phytopathogens requires them to be environmentally friendly without negative effects on rhizospheric microorganisms. The same concentration of 0.000625% Se (6.25 µg/mL) in the final suspension of all three Se NCs (which corresponds to 105.57 µg/mL for Se/AG NC, 428.08 µg/mL for Se/ST NC and 170.30 µg/mL for Se/CAR NC) was used to study their effect on bacterial growth (bactericidal, bacteriostatic, and biofilm formation effects) of the three rhizospheric bacteria. Based on our earlier studies this concentration had an antibacterial effect against the phytopathogenic bacterium that causes diseases of potato ring rot, but did not negatively affect the viability of potato plants at this concentration. In this study, using this concentration no bacteriostatic and bactericidal activity of all three Se NCs were found against based on the optical density of a bacterial suspension, agar diffusion, and intensity of biofilm formation, but Se/CAR and Se/AG NCs inhibited the growth of . The cell growth was decrease by 15-30% during the entire observation period, but the stimulation of biofilm formation by this bacterium was observed for Se/CAR NC. Se/AG NC also had bacteriostatic and antibiofilm effects on the rhizospheric bacterium . There was a 2.5-fold decrease in bacterial growth and a 30% decrease in biofilm formation, but Se/CAR NC stimulated the growth of . According to the results of the preliminary field test, an increase in potato productivity by an average of 30% was revealed after the pre-planting treatment of tubers by spraying them with Se/AG and Se/CAR NCs with the same concentration of Se of 0.000625% (6.25 µg/mL) in a final suspension. The obtained and previously published results on the positive effect of natural matrix-based Se NCs on plants open up prospects for further investigation of their effects on rhizosphere bacteria and resistance of cultivated plants to stress factors.
PubMed: 34578589
DOI: 10.3390/nano11092274 -
Microorganisms Sep 2021Aspens ( and its hybrids), economically and ecologically important fast-growing trees, are often damaged by , a rot-causing fungus. Plant-associated bacteria can be used...
Aspens ( and its hybrids), economically and ecologically important fast-growing trees, are often damaged by , a rot-causing fungus. Plant-associated bacteria can be used to increase plant growth and resistance; however, no systematic studies relating the activity of symbiotic bacteria to aspen resistance against have been conducted so far. The present pioneer study investigated the responses of two and two × genotypes to in vitro inoculations with, first, either sp. or sp. bacteria (isolated originally from hybrid aspen tissue cultures and being most closely related to and , respectively) and, in the subsequent stage, with . Both morphological parameters of in vitro-grown plants and biochemical content of their leaves, including photosynthesis pigments and secondary metabolites, were analyzed. It was found that both × genotypes, whose development in vitro was significantly damaged by , were characterized by certain responses to the studied bacteria: decreased shoot development by both sp. and sp. and increased phenol content by sp. In turn, these responses were lacking in both genotypes that showed in vitro resistance to the fungus. Moreover, these genotypes showed positive long-term growth responses to bacterial inoculation, even synergistic with the subsequent fungal inoculation. Hence, the studied bacteria were demonstrated as a potential tool for the improved in vitro propagation of fungus-resistant aspen genotypes.
PubMed: 34576797
DOI: 10.3390/microorganisms9091901 -
Frontiers in Plant Science 2021Plant-associated beneficial strains inhabiting plants grown under harsh ecosystems can help them cope with abiotic stress factors by positively influencing plant...
Plant-associated beneficial strains inhabiting plants grown under harsh ecosystems can help them cope with abiotic stress factors by positively influencing plant physiology, development, and environmental adaptation. Previously, we isolated a potential plant growth promoting strain (AXSa06) identified as , possessing 1-aminocyclopropane-1-carboxylate deaminase activity, producing indole-3-acetic acid and siderophores, as well as solubilizing inorganic phosphorus. In this study, we aimed to further evaluate the effects of AXSa06 seed inoculation on the growth of tomato seedlings under excess salt (200 mM NaCl) by deciphering their transcriptomic and metabolomic profiles. Differences in transcript levels and metabolites following AXSa06 inoculation seem likely to have contributed to the observed difference in salt adaptation of inoculated plants. In particular, inoculations exerted a positive effect on plant growth and photosynthetic parameters, imposing plants to a primed state, at which they were able to respond more robustly to salt stress probably by efficiently activating antioxidant metabolism, by dampening stress signals, by detoxifying Na, as well as by effectively assimilating carbon and nitrogen. The primed state of AXSa06-inoculated plants is supported by the increased leaf lipid peroxidation, ascorbate content, as well as the enhanced activities of antioxidant enzymes, prior to stress treatment. The identified signatory molecules of AXSa06-mediated salt tolerance included the amino acids aspartate, threonine, serine, and glutamate, as well as key genes related to ethylene or abscisic acid homeostasis and perception, and ion antiporters. Our findings represent a promising sustainable solution to improve agricultural production under the forthcoming climate change conditions.
PubMed: 34484277
DOI: 10.3389/fpls.2021.713984 -
Revista Chilena de Infectologia :... Jun 2021Indoor air quality in health centers is essential to protect the health of people. In Chile, the Community Family Health Centers (CECOSF) are places with large...
BACKGROUND
Indoor air quality in health centers is essential to protect the health of people. In Chile, the Community Family Health Centers (CECOSF) are places with large attendance of people, favoring the dissemination of microorganisms, and there are no reports of the microbial air loading these health centers.
AIM
To evaluate the microbiological indoor air quality in CECOSF-Centinela in Talcahuano, Biobío Region.
METHODS
Air samples were taken in 6 rooms of the CECOSF, every 15 days between July 2018 and June 2019, with the MAS-100 NT equipment using trypticase and Sabouraud agars. Different morphotypes of bacteria and fungi were identified by PCR.
RESULTS
The bacterial and fungal counts varied between 9.1 × 101 - 2.4 × 103 cfu/m3 and 10 - 1.5 × 102 cfu/m3, respectively. The air in the waiting room presented the highest counts, both for bacteria and fungi (P < 0.05). Staphylococcus, Enterococcus, Pseudomonas, Acinetobacter were identified, highlighting the species Staphylococcus aureus and Pseudomonas oryzihabitans, the latter described as a nosocomial pathogen. Among the fungi, Aspergillus, Meyerozyma and Rhodotorula were identified.
CONCLUSION
The indoor air of the CECOSF-Centinela presents microorganisms of importance in human health. Therefore, it is necessary to formulate more regular monitoring programs for the control of air quality inside these health centers.
Topics: Air Microbiology; Air Pollution, Indoor; Chile; Colony Count, Microbial; Environmental Monitoring; Family Health; Fungi; Humans; Pseudomonas
PubMed: 34479287
DOI: 10.4067/S0716-10182021000300324 -
Planta Mar 2021The in vitro application of rhizosphere microorganisms led to a higher rooting percentage in Pyrus Py12 rootstocks and increased plant growth of Pyrus Py170 and Prunus...
The in vitro application of rhizosphere microorganisms led to a higher rooting percentage in Pyrus Py12 rootstocks and increased plant growth of Pyrus Py170 and Prunus RP-20. The rooting of fruit tree rootstocks is the most challenging step of the in vitro propagation process. The use of rhizosphere microorganisms to promote in vitro rooting and plant growth as an alternative to the addition of chemical hormones to culture media is proposed in the present study. Explants from two Pyrus (Py170 and Py12) rootstocks and the Prunus RP-20 rootstock were inoculated with Pseudomonas oryzihabitans PGP01, Cladosporium ramotenellum PGP02 and Phoma sp. PGP03 following two different methods to determine their effects on in vitro rooting and plantlet growth. The effects of the microorganisms on the growth of fully developed Py170 and RP-20 plantlets were also studied in vitro. All experiments were conducted using vermiculite to simulate a soil system in vitro. When applied to Py12 shoots, which is a hard-to-root plant material, both C. ramotenellum PGP02 and Phoma sp. PGP03 fungi were able to increase the rooting percentage from 56.25% to 100% following auxin indole-3-butyric acid (IBA) treatment. Thus, the presence of these microorganisms clearly improved root development, inducing a higher number of roots and causing shorter roots. Better overall growth and improved stem growth of treated plants was observed when auxin treatment was replaced by co-culture with microorganisms. A root growth-promoting effect was observed on RP-20 plantlets after inoculation with C. ramotenellum PGP02, while P. oryzihabitans PGP01 increased root numbers for both Py170 and RP-20 and increased root growth over stem growth for RP-20. It was also shown that the three microorganisms P. oryzihabitans PGP01, C. ramotenellum PGP02 and Phoma sp. PGP03 were able to naturally produce auxin, including indole-3-acetic acid (IAA), at different levels. Overall, our results demonstrate that the microorganisms P. oryzihabitans PGP01 and C. ramotenellum PGP02 had beneficial effects on in vitro rooting and plantlet growth and could be applied to in vitro tissue culture as a substitute for IBA.
Topics: Cladosporium; Phoma; Plant Roots; Prunus; Pseudomonas; Pyrus; Rhizosphere; Soil Microbiology
PubMed: 33715081
DOI: 10.1007/s00425-021-03595-3 -
Plant Disease Jan 2021Muskmelon ( L.) is an important economic crop in China, which is planted on more than 376, 000 hectares with over 13 million tons of annual fruit production. In February...
Muskmelon ( L.) is an important economic crop in China, which is planted on more than 376, 000 hectares with over 13 million tons of annual fruit production. In February 2020, a serious bacterial stem and leaf rot disease on muskmelon plants was observed in greenhouses in Liguo Town, Ledong County, Hainan Province, China (18.54° N, 108.87° E), with disease incidences being approximately 10 to 12%. Initially, soft rot symptoms appeared on petioles and stems, showing yellow bacterial ooze signs, which was different from the milky white ooze produced by infection. The infected tissues of petioles, stems, and leaves eventually developed into browning and withering symptoms. To isolate and identify the causal agent, the lesion tissues were sterilized by immersion in 75% ethanol for 30 s, washed three times with sterile water, and then cut and soaked in 1 ml of distilled water for 10 min. The suspension was serially diluted and spread on Luria-Bertani agar (LB) medium. After incubation at 28°C for 24 to 36 h, the resulted bacterial colonies were tiny and were streaked on LB plate for further culture. After purification, the colonies were yellow, circular, smooth-margined, and two independent representative isolates CM-11 and CM-12 were used for further validation experiments. The electron microscope analysis showed that the pathogen was rod-shaped, with a length of 1.34 ± 0.22 μm and a width of 0.54 ± 0.06 μm (N=50), and had a single terminal flagellum. The gram staining of the two isolates was negative. Moreover, the tested strains were positive for catalase but negative for oxidase and were able to utilize D-glucose, L-arabinose, and D-mannitol. Morphological, physiological, and biochemical characteristics of both isolates were consistent with those of spp. To verify the species identity of the bacterial pathogens, genomic DNA of isolates CM-11 and CM-12 was extracted and several conserved genes were amplified and sequenced, including the 16S rRNA gene with primers 27F/1492R (GenBank MW187499 and MW187500), rpoB gene with primers V4/LAPS27 (MW201910 and MW446819), and gyrB gene with primers gyrBBAUP2/APrU (MW187501 and MW187502) (Mulet et al. 2010). In the BLAST analysis, the 16S rRNA sequences showed a 99% similarity to that of strains TH19 (LC026009), AA21 (MG571765). The rpoB and gyrB sequences showed high similarity (> 98%) to strains FDAARGOS_657. The phylogenetic tree analysis of rpoB and gyrB genes further verified that the two isolates CM-11 and CM-12 were most closely related to species. Consequently, the two pathogenic isolates CM-11 and CM-12 were identified as . Both strains of CM-11 and CM-12 were tested to accomplish Koch's postulates. Young branches of muskmelons (cultivar Yugu, 10 days after pollination) were chosen as the material for inoculation. Ten healthy detached branches were placed in 15 ml tubes by submerging the cutting wound in 5 ml of the bacterial suspension (10 CFU/ml). Ten additional branches were implemented with sterilized distilled water as a negative control. The inoculated branches were placed in a plastic box containing moistened paper at 28°C. Rotting symptoms appeared within 5 days after infection, while the control samples remained healthy. Bacteria were re-isolated from diseased tissues, and the 16S rRNA gene sequences of the isolates showed the same as those from the original pathogen. Panicle blight and grain discoloration disease caused by on rice has been described in China (Hou et al. 2020). It's also recently found that caused center blackening disease on muskmelon fruit in Korea (Choi et al. 2019). This study indicated that it was a causative agent of stem and leaf rot disease during the field growth period. To the best of our knowledge, this is the first report of causing muskmelon stem rot in China.
PubMed: 33507101
DOI: 10.1094/PDIS-01-21-0100-PDN -
JAAD Case Reports Sep 2020
PubMed: 32923568
DOI: 10.1016/j.jdcr.2020.07.040 -
Environmental Health Insights 2020The 21st century has seen a wide range of diseases resulting from zoonotic infections, of which bacterial infections have led to outbreaks of food-borne diseases.
BACKGROUND
The 21st century has seen a wide range of diseases resulting from zoonotic infections, of which bacterial infections have led to outbreaks of food-borne diseases.
AIM
The study looks at bacterial pathogen carriage by farm rats and their antimicrobial susceptibility, with the view of providing insights for antimicrobial surveillance.
METHOD
Farm rats of species where randomly collected alive from farms in Al-Ahsa using food baits. They were anaesthetize with urethane within 4 h of collection and were unconscious for the collection of samples. Basic bacteriological culturing methods were used for culturing of bacterial isolates on selective media while the Vitek 2 compact automated system (BioMerieux, Marcy L'Etoile, France) was used for bacteria identification and antimicrobial susceptibility test. Obtained data were analysed using chi-square and paired -test with significant difference between sensitive and resistance to antimicrobial susceptibility taken at < .05.
RESULTS
Isolated Gramme-negative pathogenic bacteria included strains of , strains of , and For the Gramme-positive bacteria, 4 strains of were encountered. Other Gramme-positive bacteria were coagulase-negative species (CoNS) as well as . There was a 100% resistance to the penicillins and a high resistance to imipenem (71%) by the isolates. Resistance was also high against the β-lactams by the Gramme-positive bacteria isolates. For the Gramme-negative bacteria, there was a higher than 50% resistance by the isolates against the following antibiotics: ampicillin (78%), amoxicillin/clavulanic acid (67%), cefotaxime (77%), ceftazidime (67%), cefepime (78%), norfloxacin (67%), nitrofurantoin (67%), and trimethoprim/sulfamethoxazole (78%).
CONCLUSION
The results showed high antimicrobial resistance that will need monitoring for control of spread from farm rats to humans.
PubMed: 32874093
DOI: 10.1177/1178630220942240 -
Carbohydrate Research Mar 2020Two Pseudomonas strains were isolated from the strawberry leaves. The O-antigens were obtained using phenol-water method and mild acid degradation. The following...
Two Pseudomonas strains were isolated from the strawberry leaves. The O-antigens were obtained using phenol-water method and mild acid degradation. The following structures of the O-polysaccharides were established by sugar analysis and 2D NMR spectroscopy: OPS of Pseudomonas koreensis BIM B-970G →3)-α-D-FucNAcp-(1 → 2)-β-D-Quip3NAc-(1 → 3)-α-L-6dTalp4OAc-(1→ OPS of Pseudomonas oryzihabitans BIM B-1072G →4)-α-L-FucpNAm3OAc-(1 → 3)-α-D-QuipNAc-(1 → 4)-β-D-GlcpNAc3NAcA-(1→ Where Am - acetimidoyl.
Topics: Carbohydrate Conformation; Fragaria; Magnetic Resonance Spectroscopy; Plant Leaves; Polysaccharides; Pseudomonas
PubMed: 32035290
DOI: 10.1016/j.carres.2020.107932